"Ah, Constable Stryker!" said Holmes. "Trying a new style of headgear out for size, are you?"
"Not quite, Mr. Holmes," said Stryker. "Earlier this evening, I witnessed a rather violent altercation between two individuals. I ran in to attempt to break it up, at which point both combatants absconded. One of them dropped this in his departure. I thought you'd perhaps be keen to take a look at it."
"Quite," said Holmes. "May I hang on to it? I'll be sure to let you know if I make any worthwhile observations."
"Certainly, Mr. Holmes."
And with that, the constable handed the hat over to Holmes and departed.
Holmes held the hat under his magnifier, an excited smile upon his lips.
"Well, Watson, what do we make of this? You know my methods."
I took the hat from him. In appearance, it had a foreign but humble look to it. Dull black, with a small, short crown and a much wider brim. I was quite surprised at its heft.
"Dreadfully heavy," remarked I. "Its wearer must be very fit, to be able to wear it for any interval of time and be able to lift his head."
"Yes, Watson! Very good. A rather astute observation."
He beamed at me, quite pleased, and I was filled with more than a little pride.
Holmes took the hat back from me.
"Note carefully the craftsmanship," said Holmes, applying his magnifier to the hat once again. "Entirely unique to Fengjian, a small village in China, where it is the favored style of Shaolin Monks. Particularly the sect known as the White Lotus Society, who train as warrior and worship a Fire God named Liu Kang. While their hands and feet alone can be quite lethal, they are also known to carry a rather unique concealed weapon for defence."
Holmes shook the hat by the crown and a disc of metal emerged around the rim. He carefully ran his finger along it, admiring its sharpness.
"And here is the explanation for the added weight you noted. A sharpened blade. Halloa! This hat has seen violence before. While it's clear its owner took great care of it, you can see under the glass that he has missed a small spot of blood."
At this point we both looked up and noted that a stranger had entered. A Chinese man, short and compact, but very obviously muscular.
"And this, if I am not very much mistaken, is Stryker's mystery combatant and the owner of this fine hat."
"Thank you for taking such good care of it for me, Mr. Sherlock Holmes," said our visitor, bowing deeply. "I am Kung Lao."